The present invention relates to a method of crimping an electrical wire equipped with a water-proof plug, such as a rubber plug, onto a connector terminal, as well as to a terminal crimping apparatus. More particularly, the present invention relates to a method of crimping an electrical wire and a water-proof plug onto a connector terminal by placing a connector terminal, an electrical wire, and a water-proof plug into a predetermined layout of positions, as well as to a terminal crimping apparatus.
As shown in FIG. 1, a connector terminal 42 is generally crimped onto the metal-core-exposed front end and the sheathed end of an electrical wire 41 equipped with a water-proof plug 40 made of an elastic member such as rubber. The front end of the connector terminal 42 is fitted into a given mount hole formed in an unillustrated housing. At this time, the water-proof plug 40 is brought into pressed contact with the internal surface of the mount hole of the housing, thereby ensuring the sealing characteristics of the connector terminal 42 and the electrical wire 41.
As shown in FIGS. 1 and 2, a conventional apparatus 45 used for crimping an electrical wire equipped with a water-proof plug onto a terminal crimps the metal-core-exposed front end and the sheathed end of the electrical wire 41 equipped with the water-proof plug 40 to the connector terminals 42, respectively. The terminal crimping apparatus 45 is provided with an electrical wire/terminal positioning member 47 which holds the connector terminal 42 in a given position with respect to a pair of crimping members; namely, an upper crimping member 46a and a lower crimping member 46b. the upper crimping member 46a is called xe2x80x9ca crimperxe2x80x9d and is vertically movable. The lower crimping member 46b is called xe2x80x9can anvilxe2x80x9d and is fixed on a base. Pressing force is exerted onto a given point of the connector terminal 42 from above, to thereby elastically deform an area to be crimped. As a result, the electrical wire 41 and the water-proof plug 40 are crimped onto and connected to the connector terminal 42.
At this time, the electrical wire/terminal positioning member 47 brings the metal core end of the front end of the electrical wire 41 inserted into the connector terminal 42 to a side surface 48, as well as bringing the rear end of a connecting portion of the connector terminal 42 into contact with another side surface 49. As a result, the electrical wire 41 and the connector terminal 42 are held in given positions with respect to the upper and lower crimping members 46a, 46b. 
In the foregoing conventional terminal crimping apparatus 45, the electrical wire 41 and the connector terminal 42 are held in position with respect to the upper and lower crimping members 46a, 46b. However, the water-proof plug 40 cannot be positioned.
For this reason, a housing cavity arises in the space between the rear end of the water-proof plug 40 in its insertion direction and the open end face of the mount hole formed in the housing when the connector terminal 42 is fitted into the mount hole of the housing. A water puddle is formed in the housing cavity, thereby impairing the water-proof characteristics of the housing.
For this reason, as shown in FIG. 1, in order to prevent a housing cavity when the rear end of the water-proof plug 40 is brought into alignment in its insertion direction with the open end face of the mount hole of the housing, dimension L defined by a given positional relationship of the connector terminal 42, the electrical wire 41, and the water-proof plug 40 must be set to a given value. More specifically, the dimension L has a major effect on the sealing characteristics of the housing, and there is a need to strictly control the positional relationship of the connector terminal 42, the electrical wire 41, and the water-proof plug 40, thereby resulting in a decrease in the efficiency of a crimping operation.
Although the electrical wire 41 is positioned by bringing the front end of the metal core into contact with the side surface 48 of the electrical wire/terminal positioning member 47, the electrical wire cannot be correctly positioned through an automatic assembling operation because of the extremely-low rigidity of the metal core.
It is an object of the present invention to provide a method and an apparatus, both of which place in a given positional relationship a connector terminal, an electrical wire crimped onto the connector terminal, and a water-proof plug attached to the electrical wire and are capable of being applied to an automatic assembling operation.
Additional objects, advantages, and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
These objects can be accomplished by a method of crimping an electrical wire equipped with a water-proof plug onto a terminal and a terminal crimping apparatus as defined below.
According to one aspect of the present invention, there is provided a crimping method of crimping a connector terminal onto an electrical wire equipped with an elastic water-proof plug, comprising the step of:
placing the water-proof plug in a predetermined position with respect to the front end of the connector terminal through use of positioning means.
Preferably, the electrical wire having the water-proof plug set thereon approaches the connector terminal from behind and is placed in a predetermined position through use of the positioning means.
According to another aspect of the present invention, there is provided a crimping apparatus for crimping a connector terminal onto an electrical wire equipped with an elastic water-proof plug, comprising:
a water-proof plug positioning member having a positioning protuberance used for the purpose of placing the water-proof plug in a given position with respect to the front end of the connector terminal; and
a pair of upper crimping members and a pair of lower crimping members, both of which are positioned in the vicinity of the water-proof plug positioning member and crimp the connector terminal in a given position on the electrical wire.
Preferably, the crimping apparatus further comprises a terminal positioning member which places the connector terminal in a predetermined position with respect to the upper and lower crimping members by bringing a given area of the connector terminal substantially into contact with both sides of the terminal positioning member.
More preferably, a front portion of the water-proof plug is formed into a water-proof plug cylindrical portion, and a rear portion of the water-proof plug cylinder is formed into a water-proof plug sealing portion which is larger in diameter than the water-proof plug cylindrical portion and includes a desired number of seal rings, and the front end face of the water-proof plug cylindrical portion is brought into contact with the rear surface of the positioning protuberance. Further, a circular-arc surface which has the same radius as that of the water-proof cylindrical portion is formed on the upper surface of the positioning protuberance.
Further preferably, the positioning protuberance is formed on the upper surface of the water-proof plug positioning member, and the water-proof plug positioning member is provided so as to be vertically movable while remaining in slidable contact with the rear surface of the lower crimping member. A carrier feed groove having an opening opened towards the lower crimping member is formed in said water-proof plug positioning member;
In addition, the above-mentioned object can also be attained by a method of crimping a connector terminal onto an electrical wire equipped with an elastic water-proof plug, through a crimping apparatus including an anvil and a crimper, according to the present invention, the method comprising the step of:
preparing a water-proof plug positioning member adjacent to one of the anvil and the crimper; and
bringing the water-proof plug in contact with the water-proof plug positioning member and simultaneously placing the front end of the electric wire together with the elastic water-proof plug in a predetermined position with respect to the anvil and the crimper.
Further, the above-mentioned object can also be attained by an apparatus for crimping a connector terminal onto an electrical wire equipped with an elastic water-proof plug, according to the present invention, comprising:
a first upper and lower crimping members for crimping a first portion of the connecter terminal onto the end portion of the electrical wire;
a second upper and lower crimping members disposed next to the first upper and lower crimping members for crimping a second portion of the connector terminal onto the elastic water-proof plug; and
a water-proof plug positioning member disposed in adjacent to the second lower crimping member for positioning the water-proof plug in a predetermined position with respect to the crimping members.
In the terminal crimping apparatus according to the present invention, a water-proof plug positioning member having a positioning protuberance used for positioning a water-proof plug in a given location with respect to the tip end of the connector terminal is provided in the vicinity of a pair of crimping members comprising upper and lower crimping members used for crimping an electrical wire and a water-proof plug in a given position on the connector terminal.
Accordingly, as a result of the water-proof plug positioning member with the positioning protuberance being brought into contact with the front end face of the water-proof plug attached to the electrical wire, the water-proof plug can be accurately placed in a given position with respect to the upper and lower crimping members.
Further, the terminal crimping apparatus is provided with a terminal positioning member which places the connector terminal in a given position with respect to the upper and lower crimping members by bringing a given area of the connector terminal substantially into contact with both surfaces of the terminal positioning member.
Therefore, the connector terminal which has been seperated from a carrier can be held in a given position with respect to the upper and lower crimping members while the connector terminal is being crimped onto the electrical wire having the water-proof plug by means of the upper and lower crimping members, so that a dimension of the connector terminal from the front end of the connector terminal to the rear end of the water-proof plug can be correctly maintained at a given value.
Further, the front end face of the water-proof plug sealing section is in contact with the rear surface of the positioning protuberance, and the upper surface of the positioning protuberance is formed into a concave circular-arc surface which is equal to the radius of the water-proof cylindrical portion. Accordingly, the electrical wire equipped with the water-proof plug can be readily positioned by moving the wire ahead from behind. Further, the electrical wire having the water-proof plug can be stably retained in the lateral direction during the crimping operation. Further, since the water-proof plug sealing section has much higher rigidity than that of the metal core of the electrical wire, the terminal crimping apparatus can be applied to an automatic assembling operation.
The water-proof plug positioning member is provided so as to be vertically movable while remaining in slidable contact with the rear surface of the lower crimping member, and the carrier feed groove having an opening opened towards the lower crimping member is formed in the water-proof plug positioning member.
Consequently, the connector terminal can be readily conveyed to a given position, and the connector terminal is removed from the carrier the instant the electrical wire is crimped on the connector terminal by means of the upper and lower crimping members, thereby resulting in improvements in working efficiency. Further, the terminal crimping apparatus can be applied to an automatic assembling operation.
Still other objects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments, and its several details are capable of modifications in various, obvious aspects all without departing from the invention. Accordingly, the drawing and descriptions will be regarded as illustrative in nature and not as restrictive.